Help with sims 3 custom stuff

[missyhanzus]

hii
i was wondering if anyone had the same problem as me and has anyone solved it. for starters, whenever i try to download stuff from the offical ea site for sims 3. i always get a message in firefox saying 'sims 3 no registed protocal'. something like that :| and i really don't understand it.

and then....i download stuff just from like mod the sims or something from their custom stuff and like when i download it and click on it to install so that it goes into The Sims 3 Game Launcher downloader. it doesn't download or anything

so i was wondering if anyone could help me? is there a folder where you can put stuff in or anything?